Honestly, I've always been of the opinion that NMs shouldn't be able to be claimed until they are back to full strength and all abilities reset, if they simply don't despawn. Noone should be able to benefit from someone else's work.
Another option, and I'll have to try it. Like you, I've had mobs taken when I have hate on them (a disadvantage to kiting with +Movement speed... and bard's cast times). If my hate hasn't completely worn (say a DoT) and someone takes it, I wonder what would happen if I call for help? If it works it would be no less than a vulture crew deserves.





